Attention - "!EGR" is a BAD thing!
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Teching In
Joined: Dec 2001
Posts: 387
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From: Southern IN, USA
Attention - "!EGR" is a BAD thing! Didja know that the EGR on most (if not all) OBDII cars is a GOOD THING? - It allows for advanced timing and better economy, since the PCM can be tailored to use the cooler (diluted) charge. Also, the EGR reduces pumping losses (with resulting lowered manifold vacuum) and, of course, keeps the NOX down. Removing it and not retuning the PCM curves to compensate for this change may cause excessive knock, as well as lower economy. Just a heads up!
See the excelent article in the June 2004 issue of Motor Age and the interesting letter by Al Cline of GM Powertrain in the August 2004 issue of Car Craft.
MRK
See the excelent article in the June 2004 issue of Motor Age and the interesting letter by Al Cline of GM Powertrain in the August 2004 issue of Car Craft.
MRK
Last edited by emarkay; Jun 29, 2004 at 10:06 AM. Reason: spelling
Glad somebody else agrees with this, i was talking to a local tuner about it, and the positive benefits.
i put a post up asking about it, and just got laughed at... figured if i put the reasoning behind it, people would get totally confused.
https://ls1tech.com/forums/showthrea...&highlight=egr
Ryan
i put a post up asking about it, and just got laughed at... figured if i put the reasoning behind it, people would get totally confused.
https://ls1tech.com/forums/showthrea...&highlight=egr
Ryan
I would consider !EGR an "appearance mod" as
deleting it has no benefit to maximum power
output. Though the bit about shortening the
pipe in the throttle throat might pay off, some.
And the couple pounds saved equates to, what,
1/10HP
deleting it has no benefit to maximum power
output. Though the bit about shortening the
pipe in the throttle throat might pay off, some.
And the couple pounds saved equates to, what,
1/10HP
I believe the VE table will also show an odd
"depression" in the EGR-active region, this
may change your mixture some in the areas
where fuel calcs involve both MAF and SD
inputs (but, I do not know/understand where
this "blend" goes away, only that there are
some places where the fuel calc is not purely
MAF based). Compounding the problem is the
cam change from EGR to non-EGR years, that
messes around the VE too; so just using an
'01/'02 VE table would bring in its own bit of
error. But the -form- of the table should kinda
show how EGR / no-EGR profiles differ, where
the "EGR depression" lies.
"depression" in the EGR-active region, this
may change your mixture some in the areas
where fuel calcs involve both MAF and SD
inputs (but, I do not know/understand where
this "blend" goes away, only that there are
some places where the fuel calc is not purely
MAF based). Compounding the problem is the
cam change from EGR to non-EGR years, that
messes around the VE too; so just using an
'01/'02 VE table would bring in its own bit of
error. But the -form- of the table should kinda
show how EGR / no-EGR profiles differ, where
the "EGR depression" lies.
on the HP tuners there is a EGR disable button, simply click that, and you should be alright, There are tables that show how much spark is added due to EGR, with that turned off, it should not add that timing.
Ryan
Ryan
TECH Addict
Joined: Nov 2001
Posts: 2,593
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From: TEXAS
I deleted the EGR on my 98 when I installed the LS6 intake, and I did not have any extra knock at all, in fact, I added an extra 2* to some parts of my timing table (not sure if that was due to !EGR or better flowing intake). I understand how it lowers combustion chamber temperatures by adding inert gas, but if you retuned the fuel curves to compensate for the 'new' clean air that would be taking the inert gas's place, wouldn't you make more power and not add any extra combustion temps?
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You would make more power, but it's at low part throttle
anyway so you have the option of just applying more
pedal without doing anything to hardware or software.
The "meatware" solution.
anyway so you have the option of just applying more
pedal without doing anything to hardware or software.
The "meatware" solution.
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You add an inert gas at about a 75% rate all the time - it's called Nitrogen. Just something to think about because I don't see how adding a hot exhaust gas could help improve HP. Economy and emmissions yes, but I have yet to see a top fuel car with an EGR.
Chris
Chris
This is why i left my egr on when i did my headers. I still think cutting the tube down so it doesn't stick so far into the intake is a good thing. Haven't got around to it yet though.
I'm about to install my headers soon and have the block offs for egr and air. I want to get rid of them for appearance reasons. I was curious myself as to the effects of removing the egr system. I've had a couple cars have the egr valve stick or something and they've ran like total ***. Am I looking at the same thing when I remove the egr and how much tuning am I looking at to fix the *** like qualities??
TECH Regular
Joined: Mar 2002
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Originally Posted by slow
on the HP tuners there is a EGR disable button, simply click that, and you should be alright, There are tables that show how much spark is added due to EGR, with that turned off, it should not add that timing.
Ryan
Ryan
That table is good info. It seems I pulled timing a bit too much after !EGR.
I already massaged that area in the VE table to adjust LTFTs. Though, I wasn't highly detailed with it and have not made absolutely sure of what changes did what... seemed to work as expected though. I plotted 3d graph from logs rounded to edit columns and rows... x-axis = map, y-axis = rpm and z = ltft ( average at that x-y point ) and adjusted the VE based in the area needing ltft corrections.
One of the main differences in the 1998-2000 and 2001-2002 cars is the high octane timing tables.
My 2001 didn't come with a EGR, so with that said, I guess GM engineers decided it was not needed after all.
My 2001 didn't come with a EGR, so with that said, I guess GM engineers decided it was not needed after all.
Originally Posted by emarkay
It allows for advanced timing and better economy, since the PCM can be tailored to use the cooler (diluted) charge. Also, the EGR reduces pumping losses (with resulting lowered manifold vacuum) and, of course, keeps the NOX down.
MRK
MRK
To quote a passenger, "This car makes my eyes and nose burn." 
Staging Lane
Joined: May 2004
Posts: 82
Likes: 0
From: OKC, OK
Correct me if I'm wrong, but isn't doing the !EGR necessary because at some point in the future, you may want to upgrade to a bigger intake like FAST LSX intake or the new LS2 intake that is coming out? These intakes do not have provisions for EGR, I believe...
How can replacing an inert gas (EGR) with oxygen rich air (removing EGR) be bad for performance. Last I checked more oxygen and more fuel produced more horsepower. I didn't buy my car for economy, I bought it for performance.
How can replacing an inert gas (EGR) with oxygen rich air (removing EGR) be bad for performance. Last I checked more oxygen and more fuel produced more horsepower. I didn't buy my car for economy, I bought it for performance.